RealPatrol.com, a real estate search site, claims to be "the largest U.S. archive of real estate property listings," with information on about 3.9 million properties. The site, which launched a year ago, uses automated data-capture programs, known as "spiders," to collect real estate photos and information from a range of Web sites, according to RealPatrol CEO Benjamin Ovadia. Such data-collection practices, sometimes referred to as data "scraping," are controversial in the industry and can run afoul of industry data-sharing rules and even copyright laws. Ovadia said the company, based in Cherry Hill, N.J., hasn't run into trouble yet with its data-collection practices, and that the site features information on "pretty much anything we can get eas...